Call it the Nutcracker or call it Oklahoma, but the reality of the preseason drill that showcases a defensive player going head to head with an offensive player in an effort to move the other backward is that it’s a thrilling -- yet dangerous -- proposition.

The highlight of the 2009 Bengals preseason camp for me occurred when WR Maurice Purify dominated S Roy Williams, known as one of the hardest hitters in the league, and knocked him backward in an embarrassing display for Williams. To watch it live and up close was awesome -- the speed, the power, the car crash intensity.

But it can be terrifying, especially when we hear the news that 49ers C Eric Heitmann’s neck injury that kept him out of last season occurred during a Nutcracker drill in San Francisco’s training camp.

That’s what 49ers T Joe Staley told SFGate.com (via CSN Bay Area), and it’s the disturbing result of a drill that perhaps should be taken out of practice altogether (like not giving water breaks on excruciatingly hot days).

CSN Bay Area reached former coach Mike Singletary by phone Thursday, and he said, “I have no response to that. I don't really know what Eric's prior situation was, so I'm not going to respond to that.”

According to CSN, a number of players were injured during the drill in Singletary’s first full season as head coach, and afterward team trainer Jeff Ferguson expressed concern to Singletary about the practice.

"When I sat down and explained to him why we did the Nutcracker, then he saw it as a very positive thing," Singletary said in the spring of 2010.

Hmm, that’s an interesting approach.

But Singletary also apparently tweaked the drill before last training camp to make it safer.

"I really had the coaches get together and look at the Nutcracker," he said. "Instead of just one guy getting on one side and the other guy getting on the other side and just knocking the crap out of each other, we're trying to get more out of it."

Unfortunately for Heitmann, it sounds like the tweaking didn’t go far enough.

Cassel won’t have TE Tony Moeaki to rely on; the upstart rookie is out after suffering a concussion against Denver. LG Brian Waters also left the Broncos game (groin); his status for Sunday is up in the air. Same goes for RG Ryan Lilja (foot) Starting safety Jon McGraw (knee) remains out, and his backup, Donald Washington (who was a whipping boy last week) is questionable with a calf injury.

Rookie OLB Sean Weatherspoon (knee) finally had a full week of practice. He’s questionable after missing the past four games. Pass-rushing demon John Abraham, who is playing at a Pro Bowl level this season, is also questionable with a groin. This is not a primetime game, though, so maybe it doesn’t matter if Abraham plays or not. If he does play, he’ll go up against Rams rookie LT Roger Saffold, who practiced all week despite a sore ankle.

Rams wideout Danario Alexander will probably wait one more week to return from his knee injury, though he’s at least listed as questionable.

The only Buc expected to be out of the lineup is DE Kyle Moore (shoulder). DT Ryan Sims may join him, but neither is a difference-maker individually. Regardless of who plays, Tampa will have trouble with the downhill style of Frank Gore (who, by the way, is probable with a foot).

Niners LT Joe Staley (who is as average as his first name) is out with a fibula. Thus, they’ll rely on sluggish veteran Tony Wragge.